This invention relates generally to a propulsion unit, more specifically to a marine propulsion and steering unit and still more specifically to an aerodynamic propeller type of propulsion unit commonly used to propel flat bottomed, aquatic craft sometimes referred to as "air boats". Even still more particularly, this invention relates to apparatus which permits the swivel mounting of an internal combustion engine powering a propeller and having a throttle cable so that the propeller can rotate 360.degree. in either direction starting from any position, and continue rotating if desired, while permitting continuous control of the throttle.
Prior aerodynamic propeller type propulsion devices operate to steer the aquatic craft by either mounting a pivoted rudder-like vane on the boat behind the propeller while securing the propeller in a stationary mounting, or by pivotally mounting the propeller and engine. In either case, the ability of the steering apparatus to maneuver the craft is limited. In the case of the rudder-like vane, any lateral movement of the craft always must include a forward component of motion which is often unwanted. In prior apparatus wherein the propeller is pivotally mounted, the convenience and versatility in maneuvering the craft is compromised by the inability of the pivotally mounted propulsion apparatus to be able to rotate the desired distance and continue to rotate in a given direction from any starting position. This is because the throttle control cable cannot accommodate an unlimited amount of twisting, which would accompany an unlimited amount of engine and propeller rotation, without becoming so twisted and kinked as to be incapable of functioning. Thus, if the propeller (which operates in the "pusher" configuration) were substantially facing the pilot in position to reverse the direction of the craft, and it is desired to turn the craft from its travel in the reverse direction, this can only be accomplished if the turn were in the direction from which it had come because the pivotally mounted propulsion apparatus could not continue to rotate and pass through, for example an imaginary vertical plane extending along the longitudinal axis of the craft. Thus, even though the desired rotational movement of the propeller from its present position is, say, 30.degree. , it might have to rotate back around through 330.degree. of rotation in order to prevent the throttle control cable from becoming too twisted to function.